Compression of digital audio data is used to reduce bit rate and gain the advantage of better bandwidth utilization. Transmitting data in a compressed format allows a communications link to transmit data more efficiently. By compressing data, gaps, empty fields, redundancies, and unnecessary data are eliminated thereby shortening the length of the data file.
An example of a data compression technique is the Moving Pictures Experts Group (MPEG) standard. MPEG sets forth standards for data compression and may be applied to various signals such as audio and video. MPEG utilizes encoder sub-band filters. Other examples of audio compression techniques that utilize sub-band filtering are Dolby AC-3, PAS, AACS and MP-3.
Presently there are no adaptive variable bit rate audio compression encoders. However, there is an advantage to variable bit rate efficiencies in a statistical multiplexed environment. The current state of the art is a governed, also known as rate controlled, encoder that is more suitable for multiplexing many video and audio streams together. Generally this is used to improve the overall quality of all audio and video within multiplexed video and audio streams without lowering the overall bit rate.
There is a need for an audio encoder to adapt itself, on a frame-by-frame basis, to the requirements of the audio. There is also a need for a “check and balance” method to adapt the encoder assigned bit rate to the requirements of a statistical multiplexer.